Revert "Use std::mutex instead of android::Mutex"

This reverts commit 62ad565335d4774bc5b31ced462e92566b48d197.

Bug: 36208043
Test: N/A

Change-Id: I165ab7a0718ea50a8034adb6277809e271fd762c

• include/minikin/FontCollection.h[diff]
• include/minikin/FontFamily.h[diff]
• libs/minikin/FontCollection.cpp[diff]
• libs/minikin/FontFamily.cpp[diff]
• libs/minikin/FontLanguageListCache.cpp[diff]
• libs/minikin/FontLanguageListCache.h[diff]
• libs/minikin/HbFontCache.cpp[diff]
• libs/minikin/Layout.cpp[diff]
• libs/minikin/MinikinFont.cpp[diff]
• libs/minikin/MinikinInternal.cpp[diff]
• libs/minikin/MinikinInternal.h[diff]
• tests/perftests/FontCollection.cpp[diff]
• tests/unittest/FontCollectionItemizeTest.cpp[diff]
• tests/unittest/FontFamilyTest.cpp[diff]
• tests/unittest/FontLanguageListCacheTest.cpp[diff]
• tests/unittest/HbFontCacheTest.cpp[diff]