command_buffer_gles2: Avoid crashing for lack of JNI
command_buffer_gles2: Avoid crashing for lack of JNI

Do not use Java environment to detect device model when command buffer
is built as a standalone library.
EGL API can not be used to pass the JNI from client to the library,
and the client might not be a Java application anyway.

BUG=skia:2992

Review URL: https://codereview.chromium.org/1656223003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#373195}

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