Remove nGetWidths and pass the jfloat[] as nComputeLineBreaks argument.

nGetWidths was always called just before nComputeLineBreaks. It would be
an improvement to pass the result array as the argument of
nComputeLineBreaks.

Bug: 65024629
Test: bit FrameworksCoreTests:android.text.StaticLayoutLineBreakingTest
Test: bit CtsTextTestCase:*
Test: Manually checked no regression in TextViewOnMeasurePerfTest
Test: Manually checked no regression in StaticLayoutPerfTest result
Change-Id: I566be66558a22b3a3ff79d502bebbbfec75dd065