Write a function, uncompress, that takes in a string as an argument. The input string will be formatted into multiple groups according to the following pattern:
<number><char>
for example, '2c' or '3a'.
The function should return an uncompressed version of the string where each 'char' of a group is repeated 'number' times consecutively. You may assume that the input string is well-formed according to the previously mentioned pattern.
test_00:
uncompress("2c3a1t"); // -> 'ccaaat'
test_01:
uncompress("4s2b"); // -> 'ssssbb'
test_02:
uncompress("2p1o5p"); // -> 'ppoppppp'
test_03:
uncompress("3n12e2z"); // -> 'nnneeeeeeeeeeeezz'
test_04:
uncompress("127y"); // ->'yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy'