Multiple exceptions are thrown failing to build Webgl Player when in publishing setting, enable exception drop-down is set to none. Screenshots attached.

Steps to reproduce:
1) Create new project
2) File > Build Settings > Switch platform > WebGL
3) Player Setting > Publishing Settings > Enable Exceptions > None.
4) Build/ Build and run.
5) Observe the errors in console.

Works fine with : 2018.1.a7, 2018.1.a5, 2017.3.f3

Regression on : 2018.1.b1

Environment : Occurs only in Mac

Frequency : Always

Stack Trace:

Failed running python "/Volumes/Untitled 2/Applications/Unity 2018.1.0b1/PlaybackEngines/WebGLSupport/BuildTools/Emscripten/emcc" @"/Users/admin/Desktop/2D FTP/UI/Webgl Build test/Assets/../Temp/emcc_arguments.resp"
stdout:
stderr:WARNING:root:--separate-asm works best when compiling to HTML. otherwise, you must yourself load the '.asm.js' file that is emitted separately, and must do so before loading the main '.js` fileINFO:root:generating system library: libcxx_noexcept.a... (this will be cached in "/Volumes/Untitled 2/Applications/Unity 2018.1.0b1/PlaybackEngines/WebGLSupport/BuildTools/Emscripten_FastComp_Mac/cache/asmjs/libcxx_noexcept.a" for subsequent builds)Traceback (most recent call last): File "/Volumes/Untitled 2/Applications/Unity 2018.1.0b1/PlaybackEngines/WebGLSupport/BuildTools/Emscripten/emcc", line 13, in <module> emcc.run() File "/Volumes/Untitled 2/Applications/Unity 2018.1.0b1/PlaybackEngines/WebGLSupport/BuildTools/Emscripten/emcc.py", line 1543, in run extra_files_to_link += system_libs.calculate([f for _, f in sorted(temp_files)] + extra_files_to_link, in_temp, stdout_=None, stderr_=None, forced=forced_stdlibs) File "/Volumes/Untitled 2/Applications/Unity 2018.1.0b1/PlaybackEngines/WebGLSupport/BuildTools/Emscripten/tools/system_libs.py", line 405, in calculate libfile = shared.Cache.get(name, do_create, extension=suffix) File "/Volumes/Untitled 2/Applications/Unity 2018.1.0b1/PlaybackEngines/WebGLSupport/BuildTools/Emscripten/tools/cache.py", line 97, in get shutil.copyfile(temp, cachename) File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 83, in copyfile with open(dst, 'wb') as fdst:IOError: [Errno 13] Permission denied: '/Volumes/Untitled 2/Applications/Unity 2018.1.0b1/PlaybackEngines/WebGLSupport/BuildTools/Emscripten_FastComp_Mac/cache/asmjs/libcxx_noexcept.a'
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

Exception: Failed building WebGL Player.
UnityEditor.WebGL.ProgramUtils.StartProgramChecked (System.Diagnostics.ProcessStartInfo p) (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/ProgramUtils.cs:48)
UnityEditor.WebGL.WebGlBuildPostprocessor.EmscriptenLink (BuildPostProcessArgs args, Boolean wasmBuild, System.String sourceFiles, System.String sourceFilesHash) (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/BuildPostprocessor.cs:408)
UnityEditor.WebGL.WebGlBuildPostprocessor.LinkBuild (BuildPostProcessArgs args) (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/BuildPostprocessor.cs:451)
UnityEditor.WebGL.WebGlBuildPostprocessor.PostProcess (BuildPostProcessArgs args) (at /Users/builduser/buildslave/unity/build/PlatformDependent/WebGL/Extensions/Unity.WebGL.extensions/BuildPostprocessor.cs:920)
UnityEditor.Modules.DefaultBuildPostprocessor.PostProcess (BuildPostProcessArgs args, UnityEditor.BuildProperties& outProperties) (at /Users/builduser/buildslave/unity/build/Editor/Mono/Modules/DefaultBuildPostprocessor.cs:27)
UnityEditor.PostprocessBuildPlayer.Postprocess (BuildTargetGroup targetGroup, BuildTarget target, System.String installPath, System.String companyName, System.String productName, Int32 width, Int32 height, BuildOptions options, UnityEditor.RuntimeClassRegistry usedClassRegistry, UnityEditor.Build.Reporting.BuildReport report) (at /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPipeline/PostprocessBuildPlayer.cs:285)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)
Error building Player: 3 errors
Build completed with a result of 'Failed'
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

UnityEditor.BuildPlayerWindow+BuildMethodException: 4 errors
at UnityEditor.BuildPlayerWindow+DefaultBuildMethods.BuildPlayer (BuildPlayerOptions options) [0x0021f] in /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPlayerWindowBuildMethods.cs:182
at UnityEditor.BuildPlayerWindow.CallBuildMethods (Boolean askForBuildLocation, BuildOptions defaultBuildOptions) [0x00065] in /Users/builduser/buildslave/unity/build/Editor/Mono/BuildPlayerWindowBuildMethods.cs:89
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)