fix(high contrast text): fix test tolerances

Fix: 373804722
Flag: com.android.graphics.hwui.flags.high_contrast_text_small_text_rect
Test: atest frameworks/base/core/tests/coretests/src/android/text/LayoutTest.java

Change-Id: I9d0a4078f631d3b957985e3208553d590b9c6e4f