Make the extrating faster by:
* Merge the two heavy "for .. find" loops into one
* Move the commands out of for loop rather than inside, this can reduce the
forking amount.
As a result, when install:
* buildtools-nativesdk-standalone: 14s -> 7s (50% saved)
* core-image-minimal-core2-64-toolchain: 56s -> 47s (17% saved)
[YOCTO #8404]
Signed-off-by: Robert Yang <liezhi.yang@windriver.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
