RFR: 8299255: Unexpected round errors in FreetypeFontScaler

[Toshio Nakamura]

In 'Java_sun_font_FreetypeFontScaler_createScalerContextNative', 'context->transform.xx' and '.yy' values are sometimes 65535 instead of 65536. There are unintentional double and float conversions. It may be no real harm, but I'd like to fix it.

Problem case:
context->transform.xx=**65535** yx=0 xy=0 yy=**65535** ptsz=46.590909 dmat[0]=46.590909 (float)dmat[0]=46.59090**8**

Normal case:
context->transform.xx=65536 yx=0 xy=0 yy=65536 ptsz=18.000000 dmat[0]=18.000000 (float)dmat[0]=18.000000

Test: jdk_desktop on Linux x86_64 had no regression issues.

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Commit messages:
 - 8299255: Unexpected round errors in FreetypeFontScaler

Changes: https://git.openjdk.org/jdk/pull/11763/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11763&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8299255
  Stats: 5 lines in 1 file changed: 0 ins; 0 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/11763.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11763/head:pull/11763

PR: https://git.openjdk.org/jdk/pull/11763