libc/math: Add test cases for various math API's

libc/math: Add test cases for various math API's

This patch covers test cases for left out API's in libc/math
The API's are namely:	acos,acosf,acosl,acosh,acoshf,acoshl,
			asin,asinf,asinl,asinh,asinhf,asinhl,
			atan,atanf,atanl,atanh,atanhf,atanhl,
			atan2,atan2f,atan2l,ceil,ceilf,ceill,
			copysign,copysignf,copysignl,cos,cosf,
			cosl,cosh,coshf,coshl,erf,erff,erfl,
			frexp,frexpf,frexpl,ldexp,ldexpf,ldexpl,
			log2,log2f,log2l,sin,sinf,sinl,sinh,
			sinhf,sinhl,trunc,truncf.

Signed-off-by: Vidisha Thapa <thapa.v@samsung.com>