[Xcode] With Xcode 9 developer beta, everything rebuilds when switching between comma...

[Xcode] With Xcode 9 developer beta, everything rebuilds when switching between command-line and IDE
https://bugs.webkit.org/show_bug.cgi?id=173223

Reviewed by Sam Weinig.

The rebuilds were happening due to a difference in the compiler options that the IDE and
xcodebuild were specifying. Only the IDE was passing the -index-store-path option. To make
xcodebuild pass that option, too, set CLANG_INDEX_STORE_ENABLE to YES if it is unset, and
specify an appropriate path in CLANG_INDEX_STORE_PATH.

PerformanceTests:

* MediaTime/Configurations/DebugRelease.xcconfig:

Source/bmalloc:

* Configurations/DebugRelease.xcconfig:

Source/JavaScriptCore:

* Configurations/DebugRelease.xcconfig:

Source/ThirdParty/ANGLE:

* Configurations/DebugRelease.xcconfig:

Source/ThirdParty/libwebrtc:

* Configurations/DebugRelease.xcconfig:

Source/WebCore:

* Configurations/DebugRelease.xcconfig:

Source/WebCore/PAL:

* Configurations/DebugRelease.xcconfig:

Source/WebInspectorUI:

* Configurations/DebugRelease.xcconfig:

Source/WebKit/mac:

* Configurations/DebugRelease.xcconfig:

Source/WebKit2:

* Configurations/DebugRelease.xcconfig:

Source/WTF:

* Configurations/DebugRelease.xcconfig:

Tools:

* ContentExtensionTester/Configurations/DebugRelease.xcconfig:
* DumpRenderTree/mac/Configurations/DebugRelease.xcconfig:
* ImageDiff/cg/Configurations/DebugRelease.xcconfig:
* MiniBrowser/Configurations/DebugRelease.xcconfig:
* MobileMiniBrowser/Configurations/DebugRelease.xcconfig:
* TestWebKitAPI/Configurations/DebugRelease.xcconfig:
* WebEditingTester/Configurations/DebugRelease.xcconfig:
* WebKitTestRunner/Configurations/DebugRelease.xcconfig:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@218056 268f45cc-cd09-0410-ab3c-d52691b4dbfc