With an "enhanced" version test.sun.nio.cs.mapping.CoderTest.java the charsets listed
below fail on encoding direct buffer input/output. Which indicates we have buggy
encodeBufferLoop implementation for these charsets.

EUC_JP_LINUX
x-IBM1381 (Cp1381)
x-IBM1383 (Cp1383)
x-IBM930 (Cp930)
x-IBM935 (Cp935)
x-IBM933 (Cp933)
x-IBM937 (Cp937)
x-IBM943 (Cp943)
x-IBM939 (Cp939)
x-IBM949 (Cp949)
x-IBM942 (Cp942)
x-IBM948 (Cp948)
x-IBM950 (Cp950)